1. Field of the Invention
The present invention relates to a method for treating Kaposi's sarcoma (KS), and particularly, treatments of human immunodeficiency virus-associated KS through the administration of antisense oligonucleotides complementary to basic fibroblast growth factor RNA.
2. Background of the Art
Kaposi's sarcoma (KS) is a proliferative disease of vascular origin frequently associated with Human Immunodeficiency Virus-1 (HIV-1) infection. CDC Task Force on KS and Opportunistic Infections, N. Engl. J. Med. 306:248 (1982); Safai et al Ann. Int. Med. 103:744 (1985); Havercos et al. N. Engl. J. Med 312:1518 (1985). Kaposi's sarcoma will be referred to herein as "KS", whereas HIV-1 associated Kaposi's sarcoma will be referred to herein as "AIDS-KS".
KS typically occurs as lesions in the skin, although, in most AIDS-KS patients, visceral lesions are also present. KS often arises as multiple disseminated skin lesions that in early stages resemble benign capillary hemangiomas or vascularized chronic inflammatory foci. Repeated biopsies show a progressive sarcomatous-like appearance. In more advanced stages, the lesions appear as multiple purplish to brown subcutaneous plaques or nodules, often with a verrucose surface. The characteristic histological features of KS include the proliferation of spindle-shaped cells (KS cells, considered the tumor element) and of endothelial cells, either as cellular sheets or forming new blood vessels (angiogenesis) often abnormal (slit-like spaces) containing red blood cells (CDC Task Force N. Engl. J. Med. 306:248 (1982); Safai et al Ann. Int. Med. 103:744 (1985); Havercos et al. N. Engl. J. Med 312:1518 (1985); Friedman-Kien, J. Am. Acad. Dermathol. 5:468 (1981); Gottlieb et al. Hum. Pathol. 13:882 (1982); Macnutt et al. Am. J. Pathol. 111:62 (1983)). Other KS histological features are extravascular hemorrhage with hemosiderin deposition, anaplastic fibroblast-like proliferation, and a granulation-like inflammatory reaction. Robbins et al. "Basic Pathology" p. 286 (W. B. Saunders Co., 2d ed. 1976).
In previous studies we and others have demonstrated that cultured spindle cells derived from KS lesions of AIDS patients (AIDS-KS cells) produce factors inducing autocrine and paracrine chemotactic and growth effects for cells composing the KS lesions. Nakamura et al. Science 242:426 (1988); Salahuddin Science 242:430 (1988); Ensoli et al. Science 243:223 (1989); Ensoli et al. Hematol. Oncol. Clin. North Am. 5:281 (1991); Ensoli et al. Immunol. Rev. 127:147 (1992); Roth et al. Oncogene 4:483 (1989); Miles et al. Proc. Natl. Acad. Sci. USA 89:4068 (1990); Sturzl Proc. Natl. Acad. Sci. USA 89:7046 (1992); Thompson et al. Cancer Res. 54:2670 (1991).
Supernatants from AIDS-KS cells induce normalsendothelial cells to proliferate, degrade and cross the basement membrane, followed by migration and organization into tube-like structures. Ensoli et al. Science 243:223 (1989); Ensoli et al. Hematol. Oncol. Clin. North Am. 5:281 (1991); Ensoli et al. Immunol. Rev. 127:147 (1992); Thompson et al. Cancer Res. 54:2670 (1991). These are the same events that are required for the formation of new blood vessels or angiogenesis. Folkman et al. Nature 288:551 (1980); Folkman et al. Science 235:442 (1987). In fact, we have also reported that when AIDS-KS cells are placed into the chorioallantoic membrane of 9 day-old fertilized chick eggs they induce the formation of new blood vessels. Further, when KS-cells are injected into nude mice they induced vascular lesions of mouse cell origin resembling human KS. Salahuddin, et al. Science 242:430 (1988).
Molecular analysis of the factors produced by AIDS-KS cells revealed that several factors were produced, including: interleukin-1.alpha. (IL-1.alpha.), IL-1.beta., endothelial cell growth factor (ECGF), granulocyte-monocyte colony stimulating factor (GM-CSF), transforming growth factor-.beta. (TGF-.beta.), platelet derived growth factor (PDGF), IL-6, IL-8, and basic fibroblast growth factor (bFGF). bFGF, IL-1.beta., IL-6, and IL-8, however, are produced in relatively higher quantities than the others. In particular, high steady state levels of mRNA encoding bFGF, a potent angiogenic factor, are expressed by the cells and released into the extracellular media in a biologically active form. Ensoli et al. Science 243:223 (1989); Ensoli et al. Hematol. Oncol. Clin. North Am. 5:281 (1991); Ensoli et al. Immunol. Rev. 127:147 (1992); Burgress et al. Annu. Rev. Biochem. 58:575 (1989). AIDS-KS cells were found to contain abundant storage of different bFGF protein isoforms of 18, 23, and 25 kD with both nuclear and cytosolic distribution.
Measurements of the bFGF content and lactic dehydrogenase activity in supernatants of AIDS-KS cells confirmed that bFGF release was directly related to the abundance of intracellular bFGF molecules. By using specific antibodies directed against bFGF we found that this cytokine induces the growth of AIDS-KS cells, normal endothelial cells, and other mesenchymal-derived cells (B. Ensoli, Science 243:223 (1983). Therefore, bFGF acts as both an autocrine (tumor cell specific) and paracrine (normal cell specific) growth factor. Ensoli et al. Science 243:223 (1989); Ensoli et al. Hematol. Oncol. Clin. North Am. 5:281 (1991); Ensoli et al. Immunol. Rev. 127:147 (1992).
As endothelial cell growth is the event required for angiogenesis and antibodies against bFGF blocked endothelial cell growth stimulated by AIDS-KS cells, this suggested that bFGF was responsible for angiogenesis in KS. B. Ensoli, Science 243:223 (1989). bFGF was also reported to be overexpressed in vivo, by spindle cells in human KS lesions from both AIDS-associated and classical KS. Xerri et al. Am. J. Pathol. 138:9 (1991).
A great deal of time, money, and effort has been invested in strategies to block the proliferative effects of cellular growth factors. Major resources have been invested into strategies for making antisense oligonucleotides to such growth factors in an effort to block their proliferative activities. In one experiment in vitro Kaposi's sarcoma cells were treated with antisense oligonucleotides against the cytokine IL-6. See Miles et al. Proc. Nat. Acad. Sci. USA 87:4068-4072 (1990) (embodied in International Patent Application No.: PCT/US92/04509, Publication No.: WO 92/21380 (the "Miles Application")). In the references, IL-6 was suggested to be the autocrine factor primarily responsible for proliferation of Kaposi's sarcoma cells. See Miles Application at p. 4, lines 29-33. However, IL-6 has not been shown to possess the angiogenic properties necessary for the full proliferation of Kaposi's sarcoma. Moreover, the reference indicates that relatively high dosages of antisense oligonucleotides are necessary to block the IL-6 induced proliferation of Kaposi's sarcoma. Miles Application at p. 4, lines 17-22.
Accordingly, it would be advantageous to determine the factors primarily responsible for the histogenesis (or development) of Kaposi's sarcoma and to provide methods of blocking their proliferative and angiogenic effects in vivo.